Ashless lubricating oil dispersant

ABSTRACT

Polyisobutenyl-substituted N-aminoethylethanolamines are provided which function as ashless nitrogencontaining dispersants for lubricating oil compositions.

Unite States Miller et al.

5 atent [111 3,869,514 1451 Mar. 4, 1975 ASHLESS LUBRICATING OILDISPERSANT [75] Inventors: Edward F. Miller; Walter W.

Hellmuth, both of Beacon, NY.

[73] Assignee: Texaco Inc., New York. NY. [221 Filed: July 9, 1973 [21]Appl. No.: 377,661

Related U.S. Application Data [62] Division of Ser. No. 208,978, Dec. 161971. Pat. No.

[56] References Cited UNITED STATES PATENTS 3288,774 11/1966 Cybzl260/583 P Primary E.\'aminerLeWis Gotts Assixtani E.\'aminer-D. R.Phillips Attorney, Agent, or Ffrm-T. H. Whaley; C. G. Ries [57] ABSTRACTPolyisobutenyl-substituted N-aminoethylethanolamines are provided whichfunction as ashless nitrogencontaining dispersants for lubricating oilcompositions.

4 Claims, N0 Drawings ASHLESS LUBRICATING OIL DISPERSANT Thisapplication is a division of application Ser. No. 208,978 filed December16, 1971 and issued as US. Pat. No. 3,755,433.

BACKGROUND OF THE INVENTION 1. Field of the Invention It is conventionalto employ nitrogen-containing dispersants and/or detergents informulated lubricating oil compositions. The dispersants function tokeep foreign insoluble particulates dispersed throughout the lubricantso that they can be filtered out and also to prevent the deposition andaccumulation of these bodies on critical areas of the engine.

Previously, nitrogen-containing dispersants were pre pared as a reactionproduct of an amine or polyamine with an alkenylsuceinic acid oranhydride having sufficient molecular weight to impart oil solubility tothe reaction product. More recently, dispersants have been disclosedwhich were prepared by reacting polyolefin polymers with polyaminesresulting in the production of oil-soluble products containing fromabout 0.5 to percent nitrogen. The effectiveness of a dispersant underboth stop-and-go low temperatures and high temperatures produced bycontinuous high speed driving is at best uncertain and efforts arecontinuing to improve the performance of these oil additives.

2. Description of the Prior Art US. Pat. No. 3.275.554 discloses ashlesspolyolefinsubstituted polyamines and lubricants containing theseadditives. N-2-hydroxypropyl ethylene diamine is disclosed as a speciesof a hydroxyalkyl-substituted diamine which can be reacted with thepolyolefin polymer to form a lubricating oil dispersant.

A method of preparing a general class of ethoxylated polyolefinalkylenediamine products is disclosed in a copending application, Ser.No. 155,286 filed on June 21, 1971.

SUMMARY OF THE INVENTION Polyisobutylene substitutedN-aminoethylethanolamines are provided in which the polyisobutenylradical has an average molecular weight ranging from about 600 to 5.000.These dispersants are characterized by being thermally stable. resistantto oxidation and highly effective in lubricating oil compositions over awide range of operating conditions and temperatures.

DETAILED DESCRIPTION OF THE INVENTION The compositions of the inventionare relatively high molecular weight polyisobutenyl substituted Naminoethyl ethanolamines which exhibit outstanding detergent propertieswhen employed in a lubricating oil composition. These dispersants arerepresented by the formula:

R RNI I-CHr-Clla- N-CIIz-CHr-O II in which R and R represent hydrogen ora polyisobutenyl radical having an average molecular weight ranging fromabout 600 to 5,000, at least one ofR and R being said polyisobutenylradical. The preferred materials are those in which the polyisobutenylradical has a molecular weight ranging from about 800 to 3,000 with themost preferred materials having a polyisobutenyl radical of 1,000 to1,500 molecular weight. In general, these compositions will contain fromabout 4.6 to 0.5

percent by weight of nitrogen with the preferred nitrogen content beingfrom about 2.8 to 1.8 percent as undiluted additive.

A surprising feature of the ashless dispersants of the invention istheir thermal and/or oxidation stability when employed in lubricatingoil compositions. In this connection, the structure of the compositionsof the invention is considered to be critical since previously disclosedpolyolefin substituted aminoalkylalkanolamine dispersants exhibit asusceptibility to oxidation and thermal instability that renders theadditive and lubri eating oil compositions prepared therefrom unsuitablefor some lubricant applications.

The dispersant of the invention can be employed in both mineral andsynthetic lubricating oil compositions. The mineral oil base can beparaffinic, naphthenic or a mixed mineral oil base of lubricatingviscosity. In general, these mineral oils will have an SUS viscosity atF ranging from about 75 to 1,300.

Suitable synthetic lubricating oils for preparing lubricants of theinvention include the ester base oils prepared from polyhydroxy alcoholsincluding pentaerythritol and trimethylolpropane and aliphaticmonocarboxylic acids, polyglycols and thiols, silicone fluids,polyphenyl etherthioethers and the like.

The dispersant is employed in a formulated lubricating oil at aconcentration ranging from about 0.1 to 10 weight percent with thepreferred concentration being from about 0.5 to 5 percent. Of course,oil concentrates of the dispersant can be prepared for subsequentaddition to a finished oil blend. The composition of the concentrates isnot critical and they can contain from 0.1 to 65 percent or more of thedispersant.

The following example illustrates the preparation of the specificdispersants of this invention.

EXAMPLE I Polyisobutenyl (M.W. 1,200) SubstitutedN-aminoethylethanolamine.

2,000 grams of chlorinated polyisobutylene (aver. molecular weight 1300containing about 2.77 percent chlorine) was reacted with about grams1.87 mol) of N-aminoethylethanolamine and 102 grams (0.96 mol) of sodiumcarbonate. The mixture was heated at 350F for 3 hours and 400F for 1hour. A stream of nitrogen was passed through the reaction mixture toremove the water of reaction. The reaction mixture was cooled, dilutedwith hexane and filtered. The filtrate was extracted with a mixture ofmethanol and isopropanol and the hexane solution stripped of solventunder vacuum to yield 1,989 grams of product containing 0.8% N and 0.45%CI.

EXAMPLE 11 Following the procedure of Example 1, 1,500 g of chlorinatedpolyisobutylene (Avg. M.W. 950 containing 3.84% CI), 169 g (1.62 mole)of N-aminoethyle thanolamine, and 65 g 1.6 mole) of sodium hydroxidewere reacted to give 1490 g of product containing 1.1% N and 0.36% Cl.

EXAMPLE III Using the procedure of Example I, 900 g of chlorinatedpolyisobutylene (Avg. M.W. 1300 containing 2.8% CI) and 148 g (1.42mole) of N-aminoethylethanolamine were reacted to give a productcontaining 0.90% N and 0.62% CI.

The ashless nitrogen-containing dispersant of this invention-findsparticular utility in mineral oil base motor oil compositions. Theoutstanding detergent, thermal stability and oxidation resistanceproperties of the dispersant of the invention and of formulated motoroil compositions containing this dispersant can be demon strated intests which subject the oil to severe high temperature engineconditions, such as are encountered in the Caterpillar 1-H and similarengine tests.

The dispersant properties of the additive of the invention weredetermined in Bench Sludge Tests. Formulated oil compositions containingparticulate solid matter are prepared and thoroughly agitated to evenlydisperse the particulate matter throughout the oil. The oil compositionsare centrifuged and the depth of the sediment is measured and comparedagainst a standard to show the effect of the dispersant. ln Bench SludgeTest 11. engine blow-by is included in the test mixture to increase testseverity.

The base oil used in these tests was a solvent refined mineral oilhaving a SUS viscosity at 100F of about 325. The base oil containedappropriate amounts of conventional lubricating oil additives includingan alkaline detergent, zinc dithiophosphate and polymethacrylate pourdepressant. The oil containing the dispersant additive contained theadditive of Example I at a concentration to provide 0.031% N. Theresults of the sludge tests are given in the table below.

TABLE I Bench Sludge 11 (mm sediment) Base Oil Base Oil Dispersant ofExample 1 We claim:

1. A composition represented by the formula:

in which R and R represent hydrogen or a polyisobutenyl radical havingan average molecular weight ranging from about 600 to 5,000, at leastone of R and R being said polyisobutenyl radical.

2. A composition according to claim 1 in which the polyisobutenylradical has an average molecular weight from about 800 to 3,000.

3. A composition according to claim 1 in which the polyisobutenylradical has an average molecular weight from about 1,000 to 1,500.

4. A composition according to claim 1 in which R is polyisobutenylhaving an average molecular weight of about 1,200.

1. A COMPOUND REPRESENTED BY THE FORMULA:
 2. A composition according toclaim 1 in which the polyisobutenyl radical has an average molecularweight from about 800 to 3,000.
 3. A composition according to claim 1 inwhich the polyisobutenyl radical has an average molecular weight fromabout 1,000 to 1,500.
 4. A composition according to claim 1 in which Ris polyisobutenyl having an average molecular weight of about 1,200.